Means for packing reciprocating pistons and the like.



S. ROBINSON. MEANS FOR PAGKINGREGIPROGATING PISTONS AND THE LIKE.

APPLICATION FILED FEBJS, 1909.

940,068., I Patented m 16, 1909 was. zzkzww .ters at the ends.

' ilNlTlill' ente SAMUEL RDBINSGN, Q3 PIMLICG, LGI TDON, ENG-LAND.

T 0' all whom it may concern:

Be it known that I, SAMUEL Roemson, of

Moreton street, limlico, London, SW,

England, engineer, have invented certain new. and usetul improvements inMeans tor 1 Packing Reciprocating Pistons and the Like;

and 1 do hereby declare the following to be a full, clear, and exactdescription or the in responsible for keeping steam tight the oneportion of the cylinder from ,the other as divided by said piston. Apartfrom the difficulty of getting a ring of larger external diameter thanthe cylinder into the latter, there is always the trouble that arisessooner or later from the mid-distance diameter of the cylinder wearinglarger than the 6.518111% hence a resilient packing ring that is asliding litat the middle of the cylinder is more or less tight at theends, and excessive friction results with loss of power. On the otherhand, were the piston a work ing lit at the ends of the cylinder andloose at the middle, there would be a leakage past the piston of livesteam and the accompanying waste of energy that this fault entails. ,Toovercome this disadvantage 1 pack my improved pistons with expansiverings but whose peripheral contact with the walls of the cylinder isdependent upon and varies in direct proportion to, the pressure of thesteam driving said pistons.

I will now proceed to describe my invention more particularly byreference to the accompanying drawings, in which Figure -l isa sectionalelevation. Fig. 2 is a plan of piston. Fig. 3 is a plan of piston withthe upper cover removed.

In the drawings 1 is the piston made in two halves each part beingscrewed on the piston rod 2, as shown in big. 1, with screw threads 3 ofdiffering pitches. The piston thus formed has a cavity accon'nnodl aresilient packing piston ring inc 4 1 b is divided as at b and the wea es. aped bolt head 7 inserted, the other end o. bolt, 7 being recessedwithin the piston l as Specification of Letters latent.

Application filed February 19, 19819.

Patented Nov. fill, Serial No. 478,807..

shown. A plurality of springs 8, depending in number upon the size ofthe piston, are disposed in recesses 9, formed in the inner metal of thepiston, adapted to exert an outward and radial pressure upon theresilient ring 5. 'lhe springs 8 have snags l0, adapted to keep saidsprings in place. A second and outer divided piston ring 12 is mountedbetween the piston disk flanges l immediately over the resilient ring 5,which outer ring, as a whole, for the sake of distinction, I will'terinthe steam ring, The steam ring 12 has a segmental slot 13, cut in two ormore places around its inner circumference for a serve as distancepieces when assembling the ring parts and to prevent creeping orleakageivhen the ring is at work under low pressure. 'lo preventrelative movement be tween the two rings 1 provide a pin or pins I if),on each half oithe steam ring .12, entering corresponding holes in thesteam ring 5, see Fig. 1. v The piston disks 1 are perforated is at 16with slots covering the segmental apertures 13 formed-in the steam ring12, whereby steam can enter the said ring and tend to expand sameagainst the walls of the cylinder. I

The ope ation of my invention is as follows:-'l'he piston and its partsare assembled and secured firmly in position by means of the nut 17 onpiston rod end 3, which nut may be cross pinned if necessary. The pistonis placed in the cylinder, the resilientring exerting outwardcircumferential pressure. Upon the entry of live steam to the cylinderthe steam pressure is communicated through the aperture 16 to the hackof the steam ring 12, by entering the slot 13, driving said ring outwardwith a force equal to the steam pressure. In this manner it will heobserved that the piston is automatically packed. according to the workit s has to do. oli'ectino a 'reat cconom over ex- Further in the eventof the I itis found that 5 piston of the type hereinheforedescribed'willprevent leakage when of the ordinary type tails.

' claim. g

'1; The combifiationfwith a piston having a circumferential groove, andhaving also lateral steam. passa es between the said groove and itsouter aces; of an expansionring provided with springs and arranged inthe bottom of the said groove, and an outer pecking-ring which bears onthe said expension-ring, one of the said rings being providedwithexpansion chambers for steam at itsside portions between it and theother ring, which chambers communicate with the saidjsteam passages.

. 2. The combination, with a piston having .5 a circumferential groove,and having also 'lateral' steam passages between the said groove and itsouter faces; of an expansionrmg provlded with springs and arranged inthe bottom of the said groove, and an outer packing-ring, one of thesaid rings being provided at its middle part with an annular projectionwhich engages with :1 corresponding recess in the other ring, and one ofthe seems said rings being provided with expansion chambers for steam atits side portions between it and the other ring, which chan1- betscommunicate with the said steam passages." I

3 The combination, with a piston having a circumferential groove, andhaving also lateral steam passages between the said groove and its outerfaces; ofan expansionring provided with'springs and arranged in thebottom of the said groove, and an outer packing-ring formed of segmentsand Wedge shaped packing-strips inserted between the ends of thesegments and bearing against the said expansion-ring, one of the saidrings being provided with expansion. chain

